喷漆过程中喷枪与被喷面保持在:()
A、90°
B、60°
C、45°
参考答案:A
正常人两侧肾脏每分钟生成的原尿呈约为()
A.100mL以下
B.100~500mL
C.1000~2000mL
D.180L
E.2500mL以上
The hard, out surface of the tooth is called enamel.
A.outside
B.appearance
C.outer
D.hiding